The present invention relates in general to mechanically adjustable columns, such as those used for the stepped height adjustment of chairs and furniture in general; specifically to new and useful improvements in the art with emphasis on reliability, aesthetic appearance, ease of manufacture, and competitiveness with existing devices.
Conventional adjustable columns of the type thus far described have generally fallen into two categories: those capable of storing energy by the use of compressible gases such as the commonly known "Gas Springs," and those which require considerable effort or manipulation such as those employing long screw devices, purely hydraulic means or purely clutching means. Gas springs usually provide the required effect yet are difficult to manufacture due to the close tolerances involved, are prone to leakage of the compressed gases and oil, cannot be repaired upon failure, and under certain circumstances can post safety hazards. Mechanical devices usually consist of a long screw interposed and engaged between a seat and a base in such a way that height adjustment can only be achieved by turning one relative to the other in order to reduce the effective height of the article of furniture. These are rather heavy and cumbersome devices unsuitable by today's standards.